I believe in the simplification of the game.
All our characters start out with white username colouring. As soon as our character gains access to titles, we have the option for a prefix (in front of the username) or a suffix (after the username). Only in the case of a suffix does the username get greyed out.
For some, a greyed out / less visible username might feel less valuable. For others, there is no logic behind it.
I'd say: change the colour of the usernames to white. Don't let there be a difference in colouring.